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From Peter Schuller <>
Subject Re: Garbage collection freezes cassandra node
Date Fri, 20 Jan 2012 17:30:52 GMT
> Thanks for this very helpful info. It is indeed a production site which I cannot easily
upgrade. I will try the various gc knobs and post any positive results.

*IF* your data size, or at least hot set, is small enough that you're
not extremely reliant on the current size of page cache, and in terms
of short-term relief, I recommend:

* Significantly increasing the heap size. Like double it or more.
* Decrease the occupancy trigger such that it kicks in around the time
it already does (in terms of amount of heap usage used).
* Increase the young generation size (to lessen promotion into old-gen).

Experiment on a single node, making sure you're not causing too much
disk I/O by stealing memory otherwise used by page cache. Once you
have something that works you might try slowly going back down.

/ Peter Schuller (@scode,

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